(1)select *from talbeA as  a left join tableB as b  on a.key=b.key(2)select *from talbeA as  a left join tableB as b  on a.key=b.key where b.key is null(3) select *from talbeA as  a inner join tableB as b  on a.key=b.key(4)select *from talbeA as  a right join tableB as b  on a.key=b.key (5)select *from talbeA as  a right join tableB as b  on a.key=b.key   where a.key is null(6)select *from talbeA as  a outer join tableB as b  on a.key=b.key (7)select *from talbeA as  a outer join tableB as b  on a.key=b.key where a.key is null and b.key is null